Which soil characteristic is classified under 'physical properties'?

Soil texture is classified under 'physical properties' because it refers to the size and distribution of soil particles, which fundamentally influences how soil behaves and interacts with water and air. Soil texture is determined by the proportions of sand, silt, and clay particles within the soil. This classification is crucial for understanding water retention, drainage, aeration, and the ability of roots to penetrate the soil. Physical properties like texture directly affect the soil's draining capability and how well it can hold moisture, impacting plant growth and agricultural practices.

The other choices, while important soil characteristics, fall into different categories. pH level is a chemical property that indicates acidity or alkalinity. Organic matter content pertains to the biological properties of soil, focusing on decomposed materials from living organisms. Nutrient levels also concern the soil's chemical properties, representing the availability of essential minerals and nutrients for plant growth.